U.S. Pat. No. 6,131,269 (Lee et al.) teaches that there is a problem in the field of packaging radio-frequency (RF) and millimeter-wave circuit components. The difficulty is in that parallel RF paths reduce RF signal transfer efficiency because RF energy is lost through coupling to the adjoining RF path. The publication is concerned with providing electrical or electromagnetic isolation in a lateral direction, that is, in directions parallel to the plane of the substrate. Isolation in a direction perpendicular to the substrate is provided conventionally by the metal backplane on one face of the substrate, and by a layer of metalization on the upper surface. This is achieved by forming a continuous metal isolation wall between circuit modules to increase lateral electrical isolation of closely adjacent RF or millimeter-wave circuit components mounted on a single substrate.
U.S. Pat. No. 6,991,966 (Tuominen) discloses providing a shield around the embedded component that protects against electromagnetic interference. The shield can surround the component almost entirely.